With the increasing popularity of wireless devices, many web site operators and other content providers are deploying voice driven interfaces (“voice interfaces”) for allowing users to browse their content. The voice interfaces commonly include “grammars” that define the valid utterances (words, phrases, etc.) that can occur at a given state within a browsing session. The grammars are fed to a speech recognition system and are used to interpret the user's voice entry. In web-based systems, the grammars are typically embedded as text files within voiceXML versions of web pages.
One problem with speech recognition systems is that the reliability of the recognition process tends to be inversely proportional to the size of the grammar. This poses a significant problem to content providers wishing to place large databases of products or other items online in a voice-searchable form. Specifically, if all or even a significant portion of the terms in the searchable domain are incorporated into the grammar, the grammar may become too large to provide reliable speech recognition. If, on the other hand, many terms are omitted from the grammar, the system will be incapable of recognizing many valid queries. The present invention seeks to address this and other problems.